MAVIC "MA2" wheel w/ "three leading, three trailing"

[landotter]

On May 28, 8:23 am, jim beam <[email protected]> wrote:
t's also "strange" that it's possible to get
> religiously fevered about one specific rim model while ignoring
> improvements in every element of subsequent designs. brake track
> machining being my particular favorite with arguments about "thinner"
> sidewalls being so laughably easily proven wrong, you have to seriously
> wonder.
>
>
If you're claiming that the industry has the advanced die extrusion
technology to give a thicker rim sidewall profile before machining,
you're wrong. Because of standards in the industry and legal hurdles
in France, rims may only have a precisely regulated sidewall thickness
after extrusion, machining does nothing but remove good material.
Think of the children! ;^)

 

[jim beam]

landotter wrote:
> On May 28, 8:23 am, jim beam <[email protected]> wrote:
> t's also "strange" that it's possible to get
>> religiously fevered about one specific rim model while ignoring
>> improvements in every element of subsequent designs. brake track
>> machining being my particular favorite with arguments about "thinner"
>> sidewalls being so laughably easily proven wrong, you have to seriously
>> wonder.
>>
>>
> If you're claiming that the industry has the advanced die extrusion
> technology to give a thicker rim sidewall profile before machining,
> you're wrong.

eh? what's "advanced" about changing wall thickness???

> Because of standards in the industry and legal hurdles
> in France, rims may only have a precisely regulated sidewall thickness
> after extrusion,

no, resulting thickness of finished product.

> machining does nothing but remove good material.

what, like this?
http://www.flickr.com/photos/38636024@N00/121453841/
odd how a machined surface is thicker if the extrusion can't be adjusted
to accommodate.

> Think of the children! ;^)
>
just thinking would be sufficient.

 

[landotter]

On May 28, 10:45 am, jim beam <[email protected]> wrote:
> landotter wrote:
> > On May 28, 8:23 am, jim beam <[email protected]> wrote:
> > t's also "strange" that it's possible to get
> >> religiously fevered about one specific rim model while ignoring
> >> improvements in every element of subsequent designs. brake track
> >> machining being my particular favorite with arguments about "thinner"
> >> sidewalls being so laughably easily proven wrong, you have to seriously
> >> wonder.
>
> > If you're claiming that the industry has the advanced die extrusion
> > technology to give a thicker rim sidewall profile before machining,
> > you're wrong.
>
> eh? what's "advanced" about changing wall thickness???
>
> > Because of standards in the industry and legal hurdles
> > in France, rims may only have a precisely regulated sidewall thickness
> > after extrusion,
>
> no, resulting thickness of finished product.
>
> > machining does nothing but remove good material.
>
> what, like this?http://www.flickr.com/photos/38636024@N00/121453841/
> odd how a machined surface is thicker if the extrusion can't be adjusted
> to accommodate.
>
> > Think of the children! ;^)
>
> just thinking would be sufficient.

I think your satire toggle is set to "off". ;^)

 

[[email protected]]

Sandy Leurre writes:

> Help out a layman, please. Do the math. How does one know that one
> has gone TO the limit the rim can bear? Obviously, if it bears ***
> units of tension, you don't know if it can bear ***+1. And onwards.

> Doesn't knowing the limit of spoke tension COST rims? So that one
> would know that *** units exactly is the limit? Because more than
> that exceeds the limit? So who pays to learn the limits?

You probably did not get this suggestion from reading "the Bicycle
Wheel" because it explains how you achieve that tension without rim
damage that you seem to expect.

> Won't different spoke gauges invite slightly different limits? And
> spokes from different manufacturers?

It is not dependent on the number of spokes nor their thickness. It
is entirely dependent on rim strength (cross section and material).

> So is their some kind agency - other than the manufacturer, whose
> warranty I likely invalidated - which will pay me for all the rims I
> use up in learning these limits?

Bad humor will get you nowhere!

> Or is it better to find out that I have only distorted the rim
> mildly? Am I better off having exceeded spec and relaxing tension
> and living with an imperfect wheel, so long as I have proof I have
> reached tension limit?

Why worry about it? You seem to be satisfied with the wheels you have
built (if any), so leave it that way.

> For my uninformed mind, this is a great deal of expense to achieve
> perfect knowledge of how far you can go. It's like learning what
> the maximum cornering angle you can go through a turn by measuring
> the road rash.

This is beginning to sound like bicycling experienced at the keyboard
rather than on the road and on a bicycle. If you ride you, must surely
have fallen from loss of traction, be that snow, rain or shine. If
you haven't, then you started bicycling too late in life and ride in
fear of the first occurrence.

> Sorry if such a question seems to stump SOME PEOPLE.

"SOME PEOPLE" := Sandy

Jobst Brandt

 

[jim beam]

[email protected] wrote:
> Sandy Leurre writes:
>
>> Help out a layman, please. Do the math. How does one know that one
>> has gone TO the limit the rim can bear? Obviously, if it bears ***
>> units of tension, you don't know if it can bear ***+1. And onwards.
>
>> Doesn't knowing the limit of spoke tension COST rims? So that one
>> would know that *** units exactly is the limit? Because more than
>> that exceeds the limit? So who pays to learn the limits?
>
> You probably did not get this suggestion from reading "the Bicycle
> Wheel" because it explains how you achieve that tension without rim
> damage that you seem to expect.

in your book, and repeatedly on this forum, when you state that spoke
tension should be "as high as the rim can bear", you only consider /one/
aspect of rim damage, buckling. that is a serious omission on your
part. you should acknowledge and seek to mitigate the cracking, the
other main form of damage, that results from excess spoke tension by
seeking recommended spoke tension figures from the rim manufacturer and
using a tensiometer to achieve it.

but i guess that when one knows nothing about fatigue and mistakenly
confuses tension with strength, that such errors are to be expected.

>
>> Won't different spoke gauges invite slightly different limits? And
>> spokes from different manufacturers?
>
> It is not dependent on the number of spokes nor their thickness. It
> is entirely dependent on rim strength (cross section and material).
>
>> So is their some kind agency - other than the manufacturer, whose
>> warranty I likely invalidated - which will pay me for all the rims I
>> use up in learning these limits?
>
> Bad humor will get you nowhere!
>
>> Or is it better to find out that I have only distorted the rim
>> mildly? Am I better off having exceeded spec and relaxing tension
>> and living with an imperfect wheel, so long as I have proof I have
>> reached tension limit?
>
> Why worry about it? You seem to be satisfied with the wheels you have
> built (if any), so leave it that way.
>
>> For my uninformed mind, this is a great deal of expense to achieve
>> perfect knowledge of how far you can go. It's like learning what
>> the maximum cornering angle you can go through a turn by measuring
>> the road rash.
>
> This is beginning to sound like bicycling experienced at the keyboard
> rather than on the road and on a bicycle. If you ride you, must surely
> have fallen from loss of traction, be that snow, rain or shine. If
> you haven't, then you started bicycling too late in life and ride in
> fear of the first occurrence.
>
>> Sorry if such a question seems to stump SOME PEOPLE.
>
> "SOME PEOPLE" := Sandy
>
> Jobst Brandt

 

[landotter]

On May 27, 9:50 am, Victor Kan <[email protected]> wrote:

> One problem is that the brake surface is kinda low profile so the pads
> that fit fully on my older AT400 rim with room to spare now have just
> barely enough if I have the pads exactly right, and after some more
> pad wear, they might overhang and need adjustment or replacement.

If they start to overhang, just shave them back down with a little box
plane. I usually hold the plane upside down in my palm and run the pad
over it. Good for shaving down vintage pads that still have usable
material beneath the crust. You might say, "hey my time is worth more
than that!", but it's quicker than running to the shop or making an
online purchase.

 

[Ozark Bicycle]

On May 28, 7:20 pm, jim beam <[email protected]> wrote:
> [email protected] wrote:

<snipped>

- on rim design and wheelbuilding technique -

Jobst Brandt:
> > You probably did not get this suggestion from reading "the Bicycle
> > Wheel" because it explains how you achieve that tension without rim
> > damage that you seem to expect.


jim beam:
> in your book, and repeatedly on this forum, when you state that spoke
> tension should be "as high as the rim can bear", you only consider /one/
> aspect of rim damage, buckling. that is a serious omission on your
> part. you should acknowledge and seek to mitigate the cracking, the
> other main form of damage, that results from excess spoke tension by
> seeking recommended spoke tension figures from the rim manufacturer and
> using a tensiometer to achieve it.
>

That's the salient point: Brandt's "technique" takes into account only
one indication of tension limit, the immediately apparent buckling of
the rim. The more subtle, longer term damage of cracking around the
spoke holes caused by excessive spoke tension is blamed on poor rim
design, not the outdated and now often inappropriate technique
suggested in Brandt's book.

"The Bicycle Wheel" is in dire need of an updated edition which takes
newer rim designs and the reality of steeply dished rear wheels and
the resultant tension imbalances into account.

Get with the 21st century, Jobst!

 

[* * Chas]

"Ozark Bicycle" <[email protected]> wrote in message
news:[email protected]...
> On May 28, 2:06 am, Morten Reippuert Knudsen<[email protected]> wrote:
> > Michael Press <[email protected]> wrote:
> > > In article
> > > <[email protected]>
> > > ,
> > > Ozark Bicycle
> > > <[email protected]> wrote:
> > > > When did MA-2s become great????
> > > With the MA-40, and simultaneous disappearance of all
> > > box-section, fully socketed, plugged seam, non-anodized,
> > > unmachined sidewall rims.
> >
> > I belive that Ambrosio still has an item:
> >
> > <http://www.ambrosiospa.com/provajpg/pag110.htm>
> >
>
> Note that the "Durex" (hard anodized) version is only available in
> 36H. Hmmmmm....
>

That's the only rim I've seen with cracking around the eyelets.

Chas.

 

[Ozark Bicycle]

On May 28, 8:55 pm, "* * Chas" <[email protected]> wrote:
> "Ozark Bicycle" <[email protected]> wrote in message
>
> news:[email protected]...
>
>
>
>
>
> > On May 28, 2:06 am, Morten Reippuert Knudsen<[email protected]> wrote:
> > > Michael Press <[email protected]> wrote:
> > > > In article
> > > > <[email protected]>
> > > > ,
> > > > Ozark Bicycle
> > > > <[email protected]> wrote:
> > > > > When did MA-2s become great????
> > > > With the MA-40, and simultaneous disappearance of all
> > > > box-section, fully socketed, plugged seam, non-anodized,
> > > > unmachined sidewall rims.
>
> > > I belive that Ambrosio still has an item:
>
> > > <http://www.ambrosiospa.com/provajpg/pag110.htm>
>
> > Note that the "Durex" (hard anodized) version is only available in
> > 36H. Hmmmmm....
>
> That's the only rim I've seen with cracking around the eyelets.
>

That being the Ambrosio Nexus 36H "Durex"?

 

[* * Chas]

"Ozark Bicycle" <[email protected]> wrote in message
news:[email protected]...
> On May 28, 8:55 pm, "* * Chas" <[email protected]> wrote:
> > "Ozark Bicycle" <[email protected]> wrote in
message
> >
> > news:[email protected]...
> >
> >
> >
> >
> >
> > > On May 28, 2:06 am, Morten Reippuert Knudsen<[email protected]>
wrote:
> > > > Michael Press <[email protected]> wrote:
> > > > > In article
> > > > > <[email protected]>
> > > > > ,
> > > > > Ozark Bicycle
> > > > > <[email protected]> wrote:
> > > > > > When did MA-2s become great????
> > > > > With the MA-40, and simultaneous disappearance of all
> > > > > box-section, fully socketed, plugged seam, non-anodized,
> > > > > unmachined sidewall rims.
> >
> > > > I belive that Ambrosio still has an item:
> >
> > > > <http://www.ambrosiospa.com/provajpg/pag110.htm>
> >
> > > Note that the "Durex" (hard anodized) version is only available in
> > > 36H. Hmmmmm....
> >
> > That's the only rim I've seen with cracking around the eyelets.
> >
>
> That being the Ambrosio Nexus 36H "Durex"?
>

Nope, Ambrosio 19 Extra "Durex" gray anodized. I bought them from a
friend about 20 years ago. He ran a shop and built them for himself. Campy
Record hubs, DT spokes. Specialized 700c x 25 (really about 18 or 19mm)
tires, very well made wheels.

I only used them on smooth roads and easy rides until last year when I
started riding them after work. One of the bike trails I rode a lot had
several sections where the pavement was uplifted from tree roots. I hit
these a few times in the dark hauling butt to get home.

I noticed that the rear spokes where coming loose after every ride then I
saw the cracks in the anodizing and the bulging spoke eyelets.

Aside from cheap old sewup rims without eyelets and Fiame yellow label
rims, I'd never seen spoke hole problems.

Chas.

 

[jim beam]

* * Chas wrote:
> "Ozark Bicycle" <[email protected]> wrote in message
> news:[email protected]...
>> On May 28, 8:55 pm, "* * Chas" <[email protected]> wrote:
>>> "Ozark Bicycle" <[email protected]> wrote in
> message
>>> news:[email protected]...
>>>
>>>
>>>
>>>
>>>
>>>> On May 28, 2:06 am, Morten Reippuert Knudsen<[email protected]>
> wrote:
>>>>> Michael Press <[email protected]> wrote:
>>>>>> In article
>>>>>> <[email protected]>
>>>>>> ,
>>>>>> Ozark Bicycle
>>>>>> <[email protected]> wrote:
>>>>>>> When did MA-2s become great????
>>>>>> With the MA-40, and simultaneous disappearance of all
>>>>>> box-section, fully socketed, plugged seam, non-anodized,
>>>>>> unmachined sidewall rims.
>>>>> I belive that Ambrosio still has an item:
>>>>> <http://www.ambrosiospa.com/provajpg/pag110.htm>
>>>> Note that the "Durex" (hard anodized) version is only available in
>>>> 36H. Hmmmmm....
>>> That's the only rim I've seen with cracking around the eyelets.
>>>
>> That being the Ambrosio Nexus 36H "Durex"?
>>
>
> Nope, Ambrosio 19 Extra "Durex" gray anodized. I bought them from a
> friend about 20 years ago. He ran a shop and built them for himself. Campy
> Record hubs, DT spokes. Specialized 700c x 25 (really about 18 or 19mm)
> tires, very well made wheels.
>
> I only used them on smooth roads and easy rides until last year when I
> started riding them after work. One of the bike trails I rode a lot had
> several sections where the pavement was uplifted from tree roots. I hit
> these a few times in the dark hauling butt to get home.
>
> I noticed that the rear spokes where coming loose after every ride then I
> saw the cracks in the anodizing and the bulging spoke eyelets.
>
> Aside from cheap old sewup rims without eyelets and Fiame yellow label
> rims, I'd never seen spoke hole problems.
>
> Chas.
>
>
>
what was the spoke tension?

 

[Ozark Bicycle]

On May 28, 10:14 pm, jim beam <[email protected]> wrote:
> * * Chas wrote:
> > "Ozark Bicycle" <[email protected]> wrote in message
> >news:[email protected]...
> >> On May 28, 8:55 pm, "* * Chas" <[email protected]> wrote:
> >>> "Ozark Bicycle" <[email protected]> wrote in
> > message
> >>>news:[email protected]...
>
> >>>> On May 28, 2:06 am, Morten Reippuert Knudsen<[email protected]>
> > wrote:
> >>>>> Michael Press <[email protected]> wrote:
> >>>>>> In article
> >>>>>> <[email protected]>
> >>>>>> ,
> >>>>>> Ozark Bicycle
> >>>>>> <[email protected]> wrote:
> >>>>>>> When did MA-2s become great????
> >>>>>> With the MA-40, and simultaneous disappearance of all
> >>>>>> box-section, fully socketed, plugged seam, non-anodized,
> >>>>>> unmachined sidewall rims.
> >>>>> I belive that Ambrosio still has an item:
> >>>>> <http://www.ambrosiospa.com/provajpg/pag110.htm>
> >>>> Note that the "Durex" (hard anodized) version is only available in
> >>>> 36H. Hmmmmm....
> >>> That's the only rim I've seen with cracking around the eyelets.
>
> >> That being the Ambrosio Nexus 36H "Durex"?
>
> > Nope, Ambrosio 19 Extra "Durex" gray anodized. I bought them from a
> > friend about 20 years ago. He ran a shop and built them for himself. Campy
> > Record hubs, DT spokes. Specialized 700c x 25 (really about 18 or 19mm)
> > tires, very well made wheels.
>
> > I only used them on smooth roads and easy rides until last year when I
> > started riding them after work. One of the bike trails I rode a lot had
> > several sections where the pavement was uplifted from tree roots. I hit
> > these a few times in the dark hauling butt to get home.
>
> > I noticed that the rear spokes where coming loose after every ride then I
> > saw the cracks in the anodizing and the bulging spoke eyelets.
>
> > Aside from cheap old sewup rims without eyelets and Fiame yellow label
> > rims, I'd never seen spoke hole problems.
>
> > Chas.
>
> what was the spoke tension?


Higher than the rim could bear. ;-)

 

[* * Chas]

"jim beam" <[email protected]> wrote in message
news:[email protected]...
> * * Chas wrote:
> > "Ozark Bicycle" <[email protected]> wrote in
message
> > news:[email protected]...
> >> On May 28, 8:55 pm, "* * Chas" <[email protected]> wrote:
> >>> "Ozark Bicycle" <[email protected]> wrote in
> > message
> >>> news:[email protected]...
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>> On May 28, 2:06 am, Morten Reippuert Knudsen<[email protected]>
> > wrote:
> >>>>> Michael Press <[email protected]> wrote:
> >>>>>> In article
> >>>>>> <[email protected]>
> >>>>>> ,
> >>>>>> Ozark Bicycle
> >>>>>> <[email protected]> wrote:
> >>>>>>> When did MA-2s become great????
> >>>>>> With the MA-40, and simultaneous disappearance of all
> >>>>>> box-section, fully socketed, plugged seam, non-anodized,
> >>>>>> unmachined sidewall rims.
> >>>>> I belive that Ambrosio still has an item:
> >>>>> <http://www.ambrosiospa.com/provajpg/pag110.htm>
> >>>> Note that the "Durex" (hard anodized) version is only available in
> >>>> 36H. Hmmmmm....
> >>> That's the only rim I've seen with cracking around the eyelets.
> >>>
> >> That being the Ambrosio Nexus 36H "Durex"?
> >>
> >
> > Nope, Ambrosio 19 Extra "Durex" gray anodized. I bought them from a
> > friend about 20 years ago. He ran a shop and built them for himself.
Campy
> > Record hubs, DT spokes. Specialized 700c x 25 (really about 18 or
19mm)
> > tires, very well made wheels.
> >
> > I only used them on smooth roads and easy rides until last year when I
> > started riding them after work. One of the bike trails I rode a lot
had
> > several sections where the pavement was uplifted from tree roots. I
hit
> > these a few times in the dark hauling butt to get home.
> >
> > I noticed that the rear spokes where coming loose after every ride
then I
> > saw the cracks in the anodizing and the bulging spoke eyelets.
> >
> > Aside from cheap old sewup rims without eyelets and Fiame yellow label
> > rims, I'd never seen spoke hole problems.
> >
> > Chas.
> >
> >
> >
> what was the spoke tension?

When I first started riding them the tension was very tight but even.
These rims are supposed to have a bad reputation for cracking. I think
that it was the shock from hitting the root bumps that caused the problem.

I've been building wheels for 30+ years and never saw a spoke break or a
rim crack on any wheel that I built. I never used any kind of lubricant on
the nipples, I judged tightness by feel and kept runout to under.010
overall (closer with better rims).

Chas.

 

[Victor Kan]

On May 28, 9:03 pm, landotter <[email protected]> wrote:
> On May 27, 9:50 am, Victor Kan <[email protected]> wrote:
>
> > One problem is that the brake surface is kinda low profile so the pads
> > that fit fully on my older AT400 rim with room to spare now have just
> > barely enough if I have the pads exactly right, and after some more
> > pad wear, they might overhang and need adjustment or replacement.
>
> If they start to overhang, just shave them back down with a little box
> plane...

Yep, that's part of what I meant by "adjustment", and I've done it on
my
Kool Stop Salmons on another rim with a low brake surface profile.

 

[jim beam]

* * Chas wrote:
> "jim beam" <[email protected]> wrote in message
> news:[email protected]...
>> * * Chas wrote:
>>> "Ozark Bicycle" <[email protected]> wrote in
> message
>>> news:[email protected]...
>>>> On May 28, 8:55 pm, "* * Chas" <[email protected]> wrote:
>>>>> "Ozark Bicycle" <[email protected]> wrote in
>>> message
>>>>> news:[email protected]...
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>> On May 28, 2:06 am, Morten Reippuert Knudsen<[email protected]>
>>> wrote:
>>>>>>> Michael Press <[email protected]> wrote:
>>>>>>>> In article
>>>>>>>> <[email protected]>
>>>>>>>> ,
>>>>>>>> Ozark Bicycle
>>>>>>>> <[email protected]> wrote:
>>>>>>>>> When did MA-2s become great????
>>>>>>>> With the MA-40, and simultaneous disappearance of all
>>>>>>>> box-section, fully socketed, plugged seam, non-anodized,
>>>>>>>> unmachined sidewall rims.
>>>>>>> I belive that Ambrosio still has an item:
>>>>>>> <http://www.ambrosiospa.com/provajpg/pag110.htm>
>>>>>> Note that the "Durex" (hard anodized) version is only available in
>>>>>> 36H. Hmmmmm....
>>>>> That's the only rim I've seen with cracking around the eyelets.
>>>>>
>>>> That being the Ambrosio Nexus 36H "Durex"?
>>>>
>>> Nope, Ambrosio 19 Extra "Durex" gray anodized. I bought them from a
>>> friend about 20 years ago. He ran a shop and built them for himself.
> Campy
>>> Record hubs, DT spokes. Specialized 700c x 25 (really about 18 or
> 19mm)
>>> tires, very well made wheels.
>>>
>>> I only used them on smooth roads and easy rides until last year when I
>>> started riding them after work. One of the bike trails I rode a lot
> had
>>> several sections where the pavement was uplifted from tree roots. I
> hit
>>> these a few times in the dark hauling butt to get home.
>>>
>>> I noticed that the rear spokes where coming loose after every ride
> then I
>>> saw the cracks in the anodizing and the bulging spoke eyelets.
>>>
>>> Aside from cheap old sewup rims without eyelets and Fiame yellow label
>>> rims, I'd never seen spoke hole problems.
>>>
>>> Chas.
>>>
>>>
>>>
>> what was the spoke tension?
>
> When I first started riding them the tension was very tight but even.

but if you can't quote a tension, we have to assume you didn't use a
tensiometer - and that's the problem. evenness makes no difference to
tension magnitude.

> These rims are supposed to have a bad reputation for cracking.

this reputation must be from those that build with excess tension.

> I think
> that it was the shock from hitting the root bumps that caused the problem.

radial loading reduces spoke tension, not increases it. it's simply
fatigue loading and being too close to yield that is the problem.

>
> I've been building wheels for 30+ years and never saw a spoke break or a
> rim crack on any wheel that I built. I never used any kind of lubricant on
> the nipples, I judged tightness by feel and kept runout to under.010
> overall (closer with better rims).

but you said your friend built them not yourself! and you don't know
the spoke tension. runout has /nothing/ to do with spoke tension unless
the rim is about to buckle - and if you're at that limit, tension is
already /way/ too high.

bottom line, you say the eyelets were bulging. that is incontrovertibly
excess spoke tension - any rim will crack with spoke tension high enough
to cause that.

 

[* * Chas]

"jim beam" <[email protected]> wrote in message
news:[email protected]...
> * * Chas wrote:
> > "jim beam" <[email protected]> wrote in message
> > news:[email protected]...
> >> * * Chas wrote:
> >>> "Ozark Bicycle" <[email protected]> wrote in
> > message
> >>> news:[email protected]...
> >>>> On May 28, 8:55 pm, "* * Chas" <[email protected]> wrote:
> >>>>> "Ozark Bicycle" <[email protected]> wrote in
> >>> message
> >>>>> news:[email protected]...
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>>> On May 28, 2:06 am, Morten Reippuert Knudsen<[email protected]>
> >>> wrote:
> >>>>>>> Michael Press <[email protected]> wrote:
> >>>>>>>> In article
> >>>>>>>> <[email protected]>
> >>>>>>>> ,
> >>>>>>>> Ozark Bicycle
> >>>>>>>> <[email protected]> wrote:
> >>>>>>>>> When did MA-2s become great????
> >>>>>>>> With the MA-40, and simultaneous disappearance of all
> >>>>>>>> box-section, fully socketed, plugged seam, non-anodized,
> >>>>>>>> unmachined sidewall rims.
> >>>>>>> I belive that Ambrosio still has an item:
> >>>>>>> <http://www.ambrosiospa.com/provajpg/pag110.htm>
> >>>>>> Note that the "Durex" (hard anodized) version is only available
in
> >>>>>> 36H. Hmmmmm....
> >>>>> That's the only rim I've seen with cracking around the eyelets.
> >>>>>
> >>>> That being the Ambrosio Nexus 36H "Durex"?
> >>>>
> >>> Nope, Ambrosio 19 Extra "Durex" gray anodized. I bought them from a
> >>> friend about 20 years ago. He ran a shop and built them for himself.
> > Campy
> >>> Record hubs, DT spokes. Specialized 700c x 25 (really about 18 or
> > 19mm)
> >>> tires, very well made wheels.
> >>>
> >>> I only used them on smooth roads and easy rides until last year when
I
> >>> started riding them after work. One of the bike trails I rode a lot
> > had
> >>> several sections where the pavement was uplifted from tree roots. I
> > hit
> >>> these a few times in the dark hauling butt to get home.
> >>>
> >>> I noticed that the rear spokes where coming loose after every ride
> > then I
> >>> saw the cracks in the anodizing and the bulging spoke eyelets.
> >>>
> >>> Aside from cheap old sewup rims without eyelets and Fiame yellow
label
> >>> rims, I'd never seen spoke hole problems.
> >>>
> >>> Chas.
> >>>
> >>>
> >>>
> >> what was the spoke tension?
> >
> > When I first started riding them the tension was very tight but even.
>
> but if you can't quote a tension, we have to assume you didn't use a
> tensiometer - and that's the problem. evenness makes no difference to
> tension magnitude.
>
> > These rims are supposed to have a bad reputation for cracking.
>
> this reputation must be from those that build with excess tension.
>
> > I think
> > that it was the shock from hitting the root bumps that caused the
problem.
>
> radial loading reduces spoke tension, not increases it. it's simply
> fatigue loading and being too close to yield that is the problem.
>
> >
> > I've been building wheels for 30+ years and never saw a spoke break or
a
> > rim crack on any wheel that I built. I never used any kind of
lubricant on
> > the nipples, I judged tightness by feel and kept runout to under.010
> > overall (closer with better rims).
>
> but you said your friend built them not yourself! and you don't know
> the spoke tension. runout has /nothing/ to do with spoke tension unless
> the rim is about to buckle - and if you're at that limit, tension is
> already /way/ too high.
>
> bottom line, you say the eyelets were bulging. that is incontrovertibly
> excess spoke tension - any rim will crack with spoke tension high enough
> to cause that.

Hey Jim, for over a hundred years millions of bike wheels have been built
without the benefit of tensionometers.

The only spokes that I ever broke were on Bike Boom clunkers back in the
1970s. I've bent a few rims - I hit the back of a stopped car at 30+ mph,
I skidded sideways into a curb and I pacman'd a rim in a sewer grate.

I can appreciate the benefits of using a tensionometer on a highly
stressed low spoke count wheel. I ride mostly 36 spoke wheels with a few
32 spoke wheels I've picked up along the way.

I considered buying a tensionometer several times then I laid down by
myself until the feeling passed. I figured that I'd just drive myself nuts
retensioning and retruing about 20 sets of wheels. My wheels stay true and
I rarely have to adjust any of them.

I'm still riding this Ambrosio rim for short rides on flat, smooth bike
trails. I want to watch the progress of the cracking. I've stopped
adjusting the wheel and the spokes don't feel any the worse - i.e.. they
haven't loosened any more.

As far as who built these wheels and how, they were the most accurate
wheels I've ever used and they stayed true until I hit a number of 2"-4"
high root bumps in the pavement in the dim light of dusk. The impacts
almost knocked me off of the bike.

In trying to find a retro replacement Ambrosio rim, Google searching came
up with a number of reports and complaints about this model rim being
prone to cracking. I would expect this from a 20+ year old rim that was an
early design.

Chas.

 

[Jay Beattie]

"jim beam" <[email protected]> wrote in message
news:[email protected]...
>* * Chas wrote:
>> "jim beam" <[email protected]> wrote in message
>> news:[email protected]...
>>> * * Chas wrote:
>>>> "Ozark Bicycle" <[email protected]> wrote in
>> message
>>>> news:[email protected]...
>>>>> On May 28, 8:55 pm, "* * Chas" <[email protected]> wrote:
>>>>>> "Ozark Bicycle" <[email protected]> wrote in
>>>> message
>>>>>> news:[email protected]...
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>> On May 28, 2:06 am, Morten Reippuert Knudsen<[email protected]>
>>>> wrote:
>>>>>>>> Michael Press <[email protected]> wrote:
>>>>>>>>> In article
>>>>>>>>> <[email protected]>
>>>>>>>>> ,
>>>>>>>>> Ozark Bicycle
>>>>>>>>> <[email protected]> wrote:
>>>>>>>>>> When did MA-2s become great????
>>>>>>>>> With the MA-40, and simultaneous disappearance of all
>>>>>>>>> box-section, fully socketed, plugged seam, non-anodized,
>>>>>>>>> unmachined sidewall rims.
>>>>>>>> I belive that Ambrosio still has an item:
>>>>>>>> <http://www.ambrosiospa.com/provajpg/pag110.htm>
>>>>>>> Note that the "Durex" (hard anodized) version is only available in
>>>>>>> 36H. Hmmmmm....
>>>>>> That's the only rim I've seen with cracking around the eyelets.
>>>>>>
>>>>> That being the Ambrosio Nexus 36H "Durex"?
>>>>>
>>>> Nope, Ambrosio 19 Extra "Durex" gray anodized. I bought them from a
>>>> friend about 20 years ago. He ran a shop and built them for himself.
>> Campy
>>>> Record hubs, DT spokes. Specialized 700c x 25 (really about 18 or
>> 19mm)
>>>> tires, very well made wheels.
>>>>
>>>> I only used them on smooth roads and easy rides until last year when I
>>>> started riding them after work. One of the bike trails I rode a lot
>> had
>>>> several sections where the pavement was uplifted from tree roots. I
>> hit
>>>> these a few times in the dark hauling butt to get home.
>>>>
>>>> I noticed that the rear spokes where coming loose after every ride
>> then I
>>>> saw the cracks in the anodizing and the bulging spoke eyelets.
>>>>
>>>> Aside from cheap old sewup rims without eyelets and Fiame yellow label
>>>> rims, I'd never seen spoke hole problems.
>>>>
>>>> Chas.
>>>>
>>>>
>>>>
>>> what was the spoke tension?
>>
>> When I first started riding them the tension was very tight but even.
>
> but if you can't quote a tension, we have to assume you didn't use a
> tensiometer - and that's the problem. evenness makes no difference to
> tension magnitude.
>
>> These rims are supposed to have a bad reputation for cracking.
>
> this reputation must be from those that build with excess tension.
>
>> I think
>> that it was the shock from hitting the root bumps that caused the
>> problem.
>
> radial loading reduces spoke tension, not increases it. it's simply
> fatigue loading and being too close to yield that is the problem.
>
>>
>> I've been building wheels for 30+ years and never saw a spoke break or a
>> rim crack on any wheel that I built. I never used any kind of lubricant
>> on
>> the nipples, I judged tightness by feel and kept runout to under.010
>> overall (closer with better rims).
>
> but you said your friend built them not yourself! and you don't know the
> spoke tension. runout has /nothing/ to do with spoke tension unless the
> rim is about to buckle - and if you're at that limit, tension is already
> /way/ too high.
>
> bottom line, you say the eyelets were bulging. that is incontrovertibly
> excess spoke tension - any rim will crack with spoke tension high enough
> to cause that.

True, but back in the "day" (which, according to ANSI, is any time before
noon GMT on March 27, 1983), most/many wheels were 36 hole with sockets and
120 or 126mm hub spacing. You could get tensions high enough to keep the
wheel true without any threadlock and without cracking rims. You could also
use Jobst's taco approach to determining maximum tension without causing
spoke hole cracking. It was a magical era. That approach, however, does not
translate well to the modern era of 130mm hubs, no-socket rims and low spoke
count. These days, I have to go OC rear -- or else resort to some sort of
threadlock or a much heavier rim ( I use Aeroheads) because relying on
tension alone will result in rim cracking. This is based on all my cracked
rims (which were probably in the 130kgf range -- I do have a tensiometer).
It really is time for a new chapter in the Book, maybe two (one covering the
maintenance and repair of prefab wheels).-- Jay Beattie.

 

[* * Chas]

"Jay Beattie" <[email protected]> wrote in message
news:[email protected]...
>
> "jim beam" <[email protected]> wrote in message
> news:[email protected]...
> >* * Chas wrote:
> >> "jim beam" <[email protected]> wrote in message
> >> news:[email protected]...
> >>> * * Chas wrote:
> >>>> "Ozark Bicycle" <[email protected]> wrote in
> >> message
> >>>> news:[email protected]...
> >>>>> On May 28, 8:55 pm, "* * Chas" <[email protected]>
wrote:
> >>>>>> "Ozark Bicycle" <[email protected]> wrote in
> >>>> message
> >>>>>> news:[email protected]...
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>> On May 28, 2:06 am, Morten Reippuert Knudsen<[email protected]>
> >>>> wrote:
> >>>>>>>> Michael Press <[email protected]> wrote:
> >>>>>>>>> In article
> >>>>>>>>> <[email protected]>
> >>>>>>>>> ,
> >>>>>>>>> Ozark Bicycle
> >>>>>>>>> <[email protected]> wrote:
> >>>>>>>>>> When did MA-2s become great????
> >>>>>>>>> With the MA-40, and simultaneous disappearance of all
> >>>>>>>>> box-section, fully socketed, plugged seam, non-anodized,
> >>>>>>>>> unmachined sidewall rims.
> >>>>>>>> I belive that Ambrosio still has an item:
> >>>>>>>> <http://www.ambrosiospa.com/provajpg/pag110.htm>
> >>>>>>> Note that the "Durex" (hard anodized) version is only available
in
> >>>>>>> 36H. Hmmmmm....
> >>>>>> That's the only rim I've seen with cracking around the eyelets.
> >>>>>>
> >>>>> That being the Ambrosio Nexus 36H "Durex"?
> >>>>>
> >>>> Nope, Ambrosio 19 Extra "Durex" gray anodized. I bought them from
a
> >>>> friend about 20 years ago. He ran a shop and built them for
himself.
> >> Campy
> >>>> Record hubs, DT spokes. Specialized 700c x 25 (really about 18 or
> >> 19mm)
> >>>> tires, very well made wheels.
> >>>>
> >>>> I only used them on smooth roads and easy rides until last year
when I
> >>>> started riding them after work. One of the bike trails I rode a lot
> >> had
> >>>> several sections where the pavement was uplifted from tree roots. I
> >> hit
> >>>> these a few times in the dark hauling butt to get home.
> >>>>
> >>>> I noticed that the rear spokes where coming loose after every ride
> >> then I
> >>>> saw the cracks in the anodizing and the bulging spoke eyelets.
> >>>>
> >>>> Aside from cheap old sewup rims without eyelets and Fiame yellow
label
> >>>> rims, I'd never seen spoke hole problems.
> >>>>
> >>>> Chas.
> >>>>
> >>>>
> >>>>
> >>> what was the spoke tension?
> >>
> >> When I first started riding them the tension was very tight but even.
> >
> > but if you can't quote a tension, we have to assume you didn't use a
> > tensiometer - and that's the problem. evenness makes no difference to
> > tension magnitude.
> >
> >> These rims are supposed to have a bad reputation for cracking.
> >
> > this reputation must be from those that build with excess tension.
> >
> >> I think
> >> that it was the shock from hitting the root bumps that caused the
> >> problem.
> >
> > radial loading reduces spoke tension, not increases it. it's simply
> > fatigue loading and being too close to yield that is the problem.
> >
> >>
> >> I've been building wheels for 30+ years and never saw a spoke break
or a
> >> rim crack on any wheel that I built. I never used any kind of
lubricant
> >> on
> >> the nipples, I judged tightness by feel and kept runout to under.010
> >> overall (closer with better rims).
> >
> > but you said your friend built them not yourself! and you don't know
the
> > spoke tension. runout has /nothing/ to do with spoke tension unless
the
> > rim is about to buckle - and if you're at that limit, tension is
already
> > /way/ too high.
> >
> > bottom line, you say the eyelets were bulging. that is
incontrovertibly
> > excess spoke tension - any rim will crack with spoke tension high
enough
> > to cause that.
>
> True, but back in the "day" (which, according to ANSI, is any time
before
> noon GMT on March 27, 1983), most/many wheels were 36 hole with sockets
and
> 120 or 126mm hub spacing. You could get tensions high enough to keep
the
> wheel true without any threadlock and without cracking rims. You could
also
> use Jobst's taco approach to determining maximum tension without causing
> spoke hole cracking. It was a magical era. That approach, however, does
not
> translate well to the modern era of 130mm hubs, no-socket rims and low
spoke
> count. These days, I have to go OC rear -- or else resort to some sort
of
> threadlock or a much heavier rim ( I use Aeroheads) because relying on
> tension alone will result in rim cracking. This is based on all my
cracked
> rims (which were probably in the 130kgf range -- I do have a
tensiometer).
> It really is time for a new chapter in the Book, maybe two (one covering
the
> maintenance and repair of prefab wheels).-- Jay Beattie.
>
Back in the day when I weighed 170-180 Lbs. and did 200 miles a week, I
built a lot of wheels at our shop using the lightest gage Robergel Trois
Etoile SS spokes on the front wheels and heavier butted or straight 14
gage (equivalent) on the rear. I was more interested in the wheels being
true than uniformly tensioned. I lived in the SW so corrosion was never a
problem.

I have a box full of spoke wrenches in at least 1/2 dozen sizes. Most of
them are top quality brands and I always made sure that they fit the
nipples correctly. There is a point just before the brass nipples start to
deform that I used to judge if the spokes were over tightened. I always
like to stop well short of that point.

I used Super Champion sewup and clincher rims on most of the wheels that I
built, we used to import them. Low flange 4x was my choice of spoke
patterns. I still have a few sets that I built for myself and they seem to
have withstood the test of time.

Thirty years and 50 Lbs. later, I've taken more of an interest in keeping
track of the spokes in my wheels if for no other reason than safety
issues. There's a tradeoff between spokes that are too loose and too tight
and with a 36 spoke wheel I think that the spokes can be run with a lot
less tension than most people use to build wheels today. One other point,
today's better quality rims come the factory a lot more round that the egg
shapes rims we used to use.

Chas.

 

[Jasper Janssen]

On Sun, 27 May 2007 22:40:40 -0700, jim beam <[email protected]>
wrote:

>it's not "vanished", it's simply been superseded. like carburettors and
>contact breaker ignition.

And yet I can buy a brandnew Harley 1955 frame and flathead motor if I
want to, let alone carburettors for almost any engine ever made and -- if
you're a masochist -- points-based ignition for any car that came with it
stock, as well as modern replacements.

Jasper

 

[[email protected]]

On May 29, 7:09 am, jim beam <[email protected]> wrote:
> * * Chas wrote:
> > "jim beam" <[email protected]> wrote in message
> >news:[email protected]...
> >> * * Chas wrote:
> >>> "Ozark Bicycle" <[email protected]> wrote in
> > message
> >>>news:[email protected]...
> >>>> On May 28, 8:55 pm, "* * Chas" <[email protected]> wrote:
> >>>>> "Ozark Bicycle" <[email protected]> wrote in
> >>> message
> >>>>>news:[email protected]...
>
> >>>>>> On May 28, 2:06 am, Morten Reippuert Knudsen<[email protected]>
> >>> wrote:
> >>>>>>> Michael Press <[email protected]> wrote:
> >>>>>>>> In article
> >>>>>>>> <[email protected]>
> >>>>>>>> ,
> >>>>>>>> Ozark Bicycle
> >>>>>>>> <[email protected]> wrote:
> >>>>>>>>> When did MA-2s become great????
> >>>>>>>> With the MA-40, and simultaneous disappearance of all
> >>>>>>>> box-section, fully socketed, plugged seam, non-anodized,
> >>>>>>>> unmachined sidewall rims.
> >>>>>>> I belive that Ambrosio still has an item:
> >>>>>>> <http://www.ambrosiospa.com/provajpg/pag110.htm>
> >>>>>> Note that the "Durex" (hard anodized) version is only available in
> >>>>>> 36H. Hmmmmm....
> >>>>> That's the only rim I've seen with cracking around the eyelets.
>
> >>>> That being the Ambrosio Nexus 36H "Durex"?
>
> >>> Nope, Ambrosio 19 Extra "Durex" gray anodized. I bought them from a
> >>> friend about 20 years ago. He ran a shop and built them for himself.
> > Campy
> >>> Record hubs, DT spokes. Specialized 700c x 25 (really about 18 or
> > 19mm)
> >>> tires, very well made wheels.
>
> >>> I only used them on smooth roads and easy rides until last year when I
> >>> started riding them after work. One of the bike trails I rode a lot
> > had
> >>> several sections where the pavement was uplifted from tree roots. I
> > hit
> >>> these a few times in the dark hauling butt to get home.
>
> >>> I noticed that the rear spokes where coming loose after every ride
> > then I
> >>> saw the cracks in the anodizing and the bulging spoke eyelets.
>
> >>> Aside from cheap old sewup rims without eyelets and Fiame yellow label
> >>> rims, I'd never seen spoke hole problems.
>
> >>> Chas.
>
> >> what was the spoke tension?
>
> > When I first started riding them the tension was very tight but even.
>
> but if you can't quote a tension, we have to assume you didn't use a
> tensiometer - and that's the problem. evenness makes no difference to
> tension magnitude.
>
> > These rims are supposed to have a bad reputation for cracking.
>
> this reputation must be from those that build with excess tension.
>
> > I think
> > that it was the shock from hitting the root bumps that caused the problem.
>
> radial loading reduces spoke tension, not increases it. it's simply
> fatigue loading and being too close to yield that is the problem.
>
>
>
> > I've been building wheels for 30+ years and never saw a spoke break or a
> > rim crack on any wheel that I built. I never used any kind of lubricant on
> > the nipples, I judged tightness by feel and kept runout to under.010
> > overall (closer with better rims).
>
> but you said your friend built them not yourself! and you don't know
> the spoke tension. runout has /nothing/ to do with spoke tension unless
> the rim is about to buckle - and if you're at that limit, tension is
> already /way/ too high.
>
> bottom line, you say the eyelets were bulging. that is incontrovertibly
> excess spoke tension - any rim will crack with spoke tension high enough
> to cause that.


I personally could care less about the rim brand. I am no advocate of
any particular brand. However, it is kind of a pain to have a rim that
you cannot true by hand because you need to worry about the rim
cracking. It is nice to tighten the spokes and get a lot of tension.

Andres